Well despite the weird “top layer” stuff I want to assume that everyone is somewhat familiar where data is being written and read. So please back to the actual topic:
The problem is neither any mode used for recording nor any structure but the fact, that most players likely want to get the AC3-stream embedded into a video object container (VOB) and not rawly.
Extempore two possible solutions come into my mind. The one to be chosen depends on the way of decoding the AC3 to PCM. This can be done by the internal processor of the DVD-Player or by an external device, connected via S/PDIF. In the first case, playback should be possible by multiplexing the AC3 together with a ‘dummy’ (black) video and the properly padding, time stamps, etc. to build a fully compatible video-stream. Of course, technically this isn’t the cleanest thing. But so the second wasn’t either: You can create an audio-cd, built from the AC3 files - which are blown up and embedded into regular PCM data which every audio-player can play. An external decoder should be able to recognize the “white noise” pcm-data as what it actually is (same for dts, by the way so please refer to the “Creating DTS Cd” thread also). When using DVDs, you have to add wave headers and declare the files as “wav”. However - same here: Many players won’t play wave-files they get from a file system, although this would be possible without any problems (thanks to lame programmings).
The probably best solution (as in most cases) would be to use a computer to get the data to an external DAC.